Lock stitch sewing machine



' Oct. 26, :1937. -fv..cHR|sTENsEN ET A1. 2,097,247

v .LOC'KSTIATCH SEWING 'MACHINE Ffiled Dec. i9, 1935 5 "SheetsSheet 1lllm mmm mmm l y .I raum ljllll i l-lll-IIII IHN FINN WITNESSES.- LINVENToRs Khl/55551165013@ N f Bypmmn Gaaf/g5 Saum;

54 TORNEYS.

26, 1937. N. v. cHRls'rENsEN ET AL 2,097,247

Locx sTITcHisEwING MACHINE Filed Dec. 9, 1955 Y :5 Sheets-Sheet 2 FIG I-WITNESS/3s: INVENTORS:

MrmanVL'hrI/snmf.

Oct. 26, 1937. N. v. cHRlsTENsl-:N ET AL. v2,097,247

. LOCK STITCH SEWING MACHINE Filed Dec. 9, 1935 3 Sheets-Sheet 3 By wrgSauer;

ToRNEYs. 3

Patented Oct. 26, 1937 UNITED STATES PATENT OFFICE lLoon srrrcn sswmc.MAcmNE Norman V. Christensen, Chicagorand George Sauer, Berwyn, lll.,assignors to Union Special Machine Company, Chicago, lll., akcorporationof Illinois This invention relates to sewing machine, particularly ofthe lock stitch type whereina loop taker cr rotary hook cooperates withthe needle to form seams in fabric progressively advanced I by a feedelement.

The general aim of our invention is to simplify and otherwisestructurally improve sewing machines of the specific type referred towith a view toward reducing friction and vibration to a minimum andtoward facilitating lubrication from a. storage supply of oil so thatthemachines can be run at much higher speeds than heretofore withoutoverheating and excessive wear of the parts, and without attention otherthan required for the replenishment of the oil supply at protractedintervals.y

The foregoing advantages we attain in practice, as hereinafter morefully disclosed, by providing a feed actuating shaft in the form of asleeve around the rotary hook shaft, and driving the sleeve and therotary hook shaft from the'main shaft of the machine, through atransmission enclosed for splash lubrication lin a single sealed housingcontaining a supply of lubricating oil, all of the aforesaid shafts, aswell as a feed regulating-shaft entering the housing through suitablebearings in the side wall of said housing; and by actuating the feedelement from a. pair of eccentrics on the feed shaft directly atopposite 30 sides of a bearing for said feed shaft, one of vsaideccentrics being coordinated with the feed element through a rock shaftto impart feed movements to said element and the other eccentric beingdirect-connected to the feed element to impart the necessary liftmovements thereto.v

Other objects and attendant advantages will appear from the detaileddescription which follows of the attached drawings, wherein Fig. I l isa side elevation of a lock stitch sewing rma- 40 chine convenientlyembodying Our invention, a

portion of the hollow frame ofthe machine being lbroken out toexposecertain of the mechanisin at the interior. s Fig. II is a plansectional view taken as indicated by the arrows I--ll in Fig. I with apcrltion of the work support or `bed plate ofthe inachine broken awayand sectioned to show underlying parts. y 50 Fis. m is a transversesectional View of the machine taken as indicated by the arrows m--Ii' inFigs. I and H.

Fig. IV is a fragmentary transverse staggered sectional view taken asindicated by the arrows 55 Eil-IV in Fig. H; and

, feed shaft of the machine.

tension.

Fig. V is a fragmentary transverse sectional view taken as indicated bythe arrows V--V in Fig. II. l 4

The sewing machine herein illustrated comprises a bed plate or worksupport l, with a hollow standard 2 rising therefrom at one end, saidstandard having integrally formed therewitha f hollow horizontal arm 3which overreaches the `bed plate, and which terminates in a head 4.

Guided for vertical reciprocation in the head 4 is a needle bar 5carrying the usual seaming needle 6, and a presser bar (not shown) tothe lower end of which the presser foot 'l is secured. Journaled insuitable bearings within the hollow arm 3 is the main shaft 8 of themachine, to the outer end of which is alxed a combined hand and beltwheel 9 for convenience of manual orA power operation. The usual needlethread take-up l0 operates through a vertical slot Il in the side of thehead 4, and is actuated by suitable means on the main shaft 8 vfromwhich .is also derived the movement for actuating the needle bar 5 in awell-known manner. From Figs. I and III-V it will be noted tha thehollow standard is extended as at I2 below the bed plate l, and isclosed at the bottom by a cover plate for service in accordance with ourinvention, as a sump or reservoir for lubricating oil. Extendinglongitudinally below the bed plate `is a long shaft Il which, at itsouter or left hand end (Figs. I and II) carries a loop taker or rotaryhook I5 preferably of the construction disclosed yinl application SerialNo.` 753,671, iiled November 19, 1934 by C. O. Nelson. Surrounding therotary hookshaft Il is a substantially co-extensive sleeve I6 which, aswill be understood from further explanation hereinafter,.constitutes theThe shaft I4 and coaxial sleeve I6 extend into the pendantextension i2of the hollow standard 2 through a bearing boss. i1 formed in the endwall i8 of said ex- Adjacent its outer end near the rotary hook thesleeve I6 is iournaled'in a small bearing lug i9 pendant from the worksupport.

Disposed above the rotary hook .i5 is the feed dog 2U of which thefabric-engaging teeth move up and down, as well as horizontally back andforth in suitable openings ofthe throat plate 2i of themachine, see Fig.IV. As shown in Figs. 1I and IV the feed dog 20 is secured, withcapacity for vertical adjustment, to a feedbar 22 by means of a screwit. At the rear end, the feed bar 22 is connected to a pin 25 whereofthe ends are engaged in spaced bosses of ay yoked .rocker securedto ashaft 26 whereof the ends are in turn journaled in spaced bearing lugs21y pendant from the work support I. Pivotally connected to the rocker25 at 29, is a telescopic eccentric rod 29 having a strap section 29awhich engages an eccentric 30 which, in accordance with our invention,is secured to the sleeve I6 directly to the right of the bearing I9.Aflixed to the sleeve I6 `directly to the left of the bearing I9 (Fig.II) is another eccentric 3I whereof the strap rod 32 (Fig. IV) isdirectly connected at 33 to a downwardly and forwardly curved arm 34 ofthe feed bar 22, see Fig. IV. Thus, under the action of the eccentrics30 and 3| Vand the coordinated mechanism just described, the requiredfeed and lift movements are imparted to the feed dog 22.

Within the hollow of the standard`2, the hook shaft I4 and the coaxialsleeve I5 are interconnected with the main shaft 3 of the machine by atransmission comprising a group of spur gears 35, 36, 31, 39, 39 and 40.The gears 35-39 are all of the same size and arranged as a train, thelowermost one 35 being secured to the sleeve I6 by a set screw 4 I, andthe uppermost one 38 to the main shaft by a set screw 42. Theintermediate or idler gears 36 and 31 are free to revolve between fixedcollars 43 and 44 respectively on shafts 45 and 45 supported crosswiseof the hollow of the standard 2. The types of needle thread take-up Iand rotary hook I5 employed in the machine necessitate rotation of themain shaft 8 in the direction of the arrow in Fig. III, and the sleeveI6.in the opposite direction as also indicated by the arrow in Fig. IIIand thus entails the use of the two intervening idler gears 36 and 31.In other machines where the above described condition does not obtain, asingle idler may be substituted in place of the two idlers 36 and 31. Asshown in Fig. I the right hand end of the rotary hook shaft I4 extendsbeyond the gear 35 and has affixed to it the gear 39 which meshes withthe gear wheel 40, the latter being formed integral with or secured tothe gear wheel 36. 'I'he ratio of the gear wheels 39, 40 is, in thisinstance, one to two, so that the rotary hook shaft I4 is caused torotate twice for each rotation of the sleeve I in the same direction asthe latter. It is, however, to be understood that when required forgreater or lesser relative speeds of the rotary hook shaft,fthe ratiobetween the gears 39 and 40 can be changed, as required.

f Our machine is also provided with an improved and simplified feedregulating mechanism which includes'a shaft 41 in parallelism with therotary hook shaft I4 and the sleeve I8 below the work support I. Theright hand end of the regulating shaft 41 (Fig. II) extends through abearing opening 43 in the front wall of the pendant extension I2 of thestandard 2 into the hollow of the latter and has secured to it a finger49. A torsion spring 50 with one end thereof engaging a fixed lug 5I,within the hollow of the standard 2 and with the other end thereofbearing against a lateral projection 49a of the finger 49, tends torotate the regulating shaft 41 in the direction of the arrow in Fig. IIIto yieldingly maintain said finger in engagement with the rounded innerend of an adjusting screw 52. As shown, the adjusting screw 5,2 hasthreaded engagement with the lug 5I and extends upwardly at an anglethrough a bearing boss 53 in the side wall 54 of the standard 2 to theexterior where it is provided with a manipulating linger knob 55. Nearits left hand end (Fig. II) the regulating shaft 41 is supported in abearing lug 56 pendant from the work support. Pivotally connected at 51to the end of an arm 58 on the regulating shaft 41 beyond the bearing 56is a lazy bar or link 59 which is in turn connected at 60 to the tubularsection 29h of the telescopic eccentric strap rod 29.

Except for the arrangement of the eccentrics 30 and 3|, and theadjusting means for the regulating shaft, the illustrated feed mechanismis generally similar in construction and operation to that featured inU. S. Fatent 2,035,508 granted on March 31, 1936. to George Sauer, oneof the present applicants `iointly with Clarence C. Smith.

From the foregoing, it will be apparent that the sewing machine of thepresent invention is simple in construction by virtue of the coaxialarrangement of the rotary hook shaft I4 and the feed actuating sleeveI6. Due to placement of the feed and lift eccentrics 30 and 3| directlyat opposite sides of the far bearing I9 for the sleeve I6 and by directconnection of the ylift eccentric strap to the feed bar 22, the actionof the eccentrics is balanced and the operation of the feed mechanism asa whole rendered quieter and smoother. In our machine, the sleeve I6 isrotated at half the speed of the rotary hook shaft I4 in the samedirection, from which it follows that the relative surface speed of saidshaft in its bearing is only half the surface speed which it would havein a stationary bearing or bearings. Obviously, this results in lessfriction and wear, the wear being `uniformly distributed between thesleeve I9 (which is internally eased for the greater part of its lengthas shown in dotted lines in Fig. II), the relatively short contactingportions of the shaft I4, and the surfaces of the relatively smallremotely spaced bearings I1 and I9 for said sleeve. During operation ofthe machine, the transmission gears carry up oil from the supplymaintained in the reservoir I2 at the bottom of the closed housingconstituted by the hollow standard 2, and splash the oil about so thatnot only are they themselves adequately lubricated at all times, but thebearings for the several shafts as well, part of the splashed oil alsonding its way between the rotary hook shaft I4 and the sleeve I6. Themachine' can thus be safely operated at high speeds in the productionvof upwards of 5000 stitches per minute without overheating or incurringexcessive wear, and without requiring attention except at veryinfrequent intervals to renew or replenish the oil in the reservoir I2.

Having thus described our invention, we claim:

1. In a lock stitch sewing machine. a rotary hook; a feed element a mainshaft; a pair of coaxial auxiliary shafts respectively carrying therotary hook and means for actuating the feed element; a closed oilhousing into which all three shafts extend; and a transmissioninterconnecting the three shafts within the housing, said transmission,said shafts and the bearings for the latter being lubricated by the oilin the housing.

2. In a lock stitch sewing machine, a rotary hook; a feed element;a'main shaft, a shaft for the rotary hook; ap shaft in the form of asleeve surrounding the rotaryhook shaft and carrying means for actuatingthe feed element; a closed oil housing into which all three shaftsextend; and a transmission interconnecting the three shafts within thehousing, said transmission, said shafts and the bearings for the latterbeing lubricated by the oil in the housing.

3. In a lock stitch sewing machine, a rotary hook; a feed element; amain shaft; a parallel shaft for the rotary hook; -a shaft in the formof a sleeve surrounding the rotary hook shaft and carrying means foractuating the feed element; a closed oil housing` into which all threeshafts extend; and a group of intermeshing gear wheels interconnectingthe three shafts within the housing, said gears, said shafts and thebearings for them being lubricated by the oil in the housing.

4. In a lock stitch sewing machine, a rotary hook; a feed element; amain shaft; a parallel shaft for the rotary hook; a shaft in the form ofa sleeve surrounding the rotary hook shaft and carrying means foractuating the feed element; a closed oil housing into which all threeshafts extend; and a group of intermeshing gear wheels interconnectingthe three shafts within the housing. the ratios of the gear wheels beingsuch that the rotary hook shaft is driven at a higher speed than thesleeve in the same direction.

5. In a lock stitch sewing machine, a. rotary hook; a feed element; amain shaft; a parallel shaft for the rotary hook; a shaft in the form ofa sleeve surrounding the rotary hook shaft and carrying means foractuating the feed element; a closed oil housing into which all threeshafts extend; and a group of intermeshing gear wheels interconnectingthe three shafts within the lubricant housing, the ratios of the gearwheels being such that the rotary hook shaft is driven at twice thespeed of the sleeve in the same direction.

6. In a lock stitch sewing machine, a rotary hook; a feed element; amain shaft; a parallel shaft for the rotary hook; a shaft in the form ofa sleeve surrounding the rotary hook shaft and carrying means foractuating the feed element; a closed oil housing into which all threeshafts extend; and a group of intermeshing gear wheels interconnectingthe three shafts within the housing, the ratios of the gear wheels beingsuch that the sleeve is driven in unison with the main shaft, and therotary hook shaft driven at a higher speed in the same direction as thesleeve.

7. In a lock stitch sewing machine, a work support; a hollow standardwith a horizontal arm overreaching the work support, said standardhaving an extension below the work support and being closed at thebottom to serve as a reservoir for oil; a main shaft journaled in thehorizontal arm; a rotary hook; a feed element; co-axial shafts below thework support respectively carrying the rotary hook, and means foractuating the feed element, said shafts extending. through a bearinginto the downward extension of the standard; and a transmissioninterconnecting the main shaft, the rotary hook shaft, and the feedactuating shaft within the hollow of the standard.

8. In a lock stitch sewing machine, a work support; a hollow standardwith a horizontal arm overreaching the work support, said standardhaving an extension below the work support and being closed at thebottom to serve as a reservoir for oil; a main shaft journaled in thehorizontal arm; a rotary hook; a feed element; a shaft below the worksupport carrying the rotary hook; a sleeve surrounding the rotary hookshaft and carrying means for actuating the feed element, said rotaryhook shaft and sleeve extending through a bearing into the downwardextension of the standard; and a transmission interconnecting the mainshaft, the rotary hook shaft and the sleeve within the hollow of thestandard.

9. In a lock stitch sewing machine, a rotary hook; a feed element; amain shaft; a pair of auxiliary shafts respectively carrying the rotaryhook, and means for actuating the feed element; a feed regulating shaft;a closed oil housing into which all four shafts extend; a transmissioninterconnecting the main shaft, the rotary hook shaft and the feedactuating shaft within the housing; and means extending to the exteriorof the housing for adjusting the feed regulating shaft. Y

10. In a lock stitch sewing machine, a work support; a hollow standardwith a horizontal arm overreaching the work support, said standardhaving an extension below the work support and being closed at thebottom to serve as a reservoir for oil; a main shaft journaled in thehorizontal arm; a rotary hook; a feed element; a shaft below the worksupport carrying the rotary hook; a sleeve surrounding the rotary hookshaft and carrying means for actuating the feed element; a feedregulating shaft also below the work support and extending through abearing into the downward extension of the standard; a transmissioninterconnecting the main shaft, the rotary hook shaft and the sleevewithin the standard; and feed regulating shaft adjusting meansaccessible above the work plate and extending into the hollow of thestandard.

11. In a lock stitch sewing machine, a rotary hook; a feed bar; a rotaryhook shaft; and a coaxial feed actuating shaft with two eccentricsthereon, one of said eccentrics being connected to the feed bar througha rock shaft to impart feed movements to said bar, and the othereccentric being direct-connected to the feed bar to impart liftmovements thereto.

1'2. In a lock stitch sewing machine, a rotary hook; a feed bar; arotary hook shaft; a coaxial feed actuating shaft with two eccentricsthereon; and straps surrounding said eccentrics, one of said strapsbeing connected to the feed bar through a rock shaft to impart feedmovements to said feed bar, and the other of said straps beingdirect-connected to the feed bar to impart lift movements thereto.

13. In a lock stitch sewing machine, a rotary hook; a feed bar; a rotaryhook shaft; a coaxial feed actuating shaft supportednear opposite endsthereof in remotely spaced bearings; and a pair of eccentrics on saidshaft directly at opposite sidesof one of the bearings, one of saideccentrics being connected to the feed bar through a rock shaft toimpart feed movements to said bar, and the other eccentric beingdirectconnected to the feed bar to impart lift movements thereto.

14. In a lock stitch sewing machine, a needle; a cooperating rotaryhook; a. needle actuating shaft; a feed element; a pair of coaxialauxiliary shafts respectively carrying the rotary hook and means foractuating the feed element; and transmission means coordinating saidshafts with one of them serving as a power shaft from which the othersare driven.

15. In a lock stitch sewing machine, a rotary NORMAN V. CI-IRISTENSEN.GEORGE SAUER.

